On NOVA, a team of carpenters, timber framers, engineers, and historians recreate a medieval throwing machine called a trebuchet. This adapted video segment explores how understanding energy transfer informs their design.

See potential energy convert to kinetic energy in this interactive activity from WGBH that shows a roller coaster in action.

In this video segment from NASA, robotics researcher Ayanna Howard uses engineering to improve the intelligence of robots in space exploration.

In this video segment adapted from NOVA scienceNOW, learn how what you eat, drink, or smoke may affect the instructions your epigenomes send to your genes, and as a result, change how your DNA is expressed.

Franklin works with Laverne to create a budget for a job painting a room, in this video segment from TV 411.

Harry estimates how long it will take him to get to the front of a long ticket line in this Cyberchase video segment.

In this media-rich lesson, students explore some of the ethical, legal, and social issues related to personal genetic testing and genome sequencing.

In this video excerpt from NOVA, learn about the advantages, disadvantages, and ethical implications of preimplantation genetic diagnosis, or PGD, a technique used to screen embryos created through in vitro fertilization for diseases.

In this NASA video, scientists describe how the Extreme Ultraviolet Variability Experiment will sample and track the Sun's ultraviolet irradiance, providing a detailed time sequence of extreme ultraviolet output -- data that can provide advance warning for potentially disruptive energy bursts.

In this adapted video segment, ZOOM guest Tommy takes us on a tour of the Florida Everglades. He describes what makes a wetland biome unique, including the soil, precipitation, and biodiversity.

How much radiation are we exposed to every day? Find out in this video segment adapted from FRONTLINE.

This video segment adapted from NOVA tells the story of two scientists who inadvertently discovered microwave radiation that is now believed to be heat left over from the Big Bang.

This video segment from Evolution: "Darwin's Dangerous Idea" illustrates the remarkable camouflage of a praying mantis against its leafy backdrop.

This video from Evolution explores the evolution of humans from a common ancestor of humans, chimpanzees, and other apes.

This video from Evolution highlights Charles Darwin's personal struggle to bring to light his theory of evolution through natural selection.

In this video from Evolution, an exploration of multi-drug resistant tuberculosis in the Russian prison system highlights one reason it is important to understand evolution.

In this video segment adapted from NASA, students in Matsuyama City, Japan, interview Expedition 8 Commander and NASA Science Officer Mike Foale and Flight Engineer Alexander Kaleri about life and work aboard the International Space Station.

In this video segment adapted from ZOOM, the cast investigates how the pitch of sound changes when they strike a variety of glasses filled with different amounts and types of liquids.

Can a fresh lemon power a digital clock? In this video segment adapted from ZOOM, the cast shows you how this can be done and, in the process, discover how kids can be a part of an electric circuit.

In this video segment from Religion & Ethics Newsweekly, learn about Muslims in Lawrenceville, Georgia, their plans to build an Islamic cemetery and the stiff objections from their Christian neighbors.